Wine is made from grapes so it must be vegan, right? Wrong. You don’t have to be a wine geek to know that certain wines, especially whites, are clarified—through a process called fining—to improve their clarity and remove protein, yeast, and other particles that might affect the wine’s flavor palate.

Fining is usually accomplished using animal-derived products such as egg whites, the milk protein casein, or a gelatin derived from fish bladders called isinglass. Though these fining agents are removed after the process, some particles remain in the wine, which means they are vegan-verboten.

Luckily, other substances such as types of clay or limestone can be used to fine wines. Many winemakers, including some high-end household names, are pursuing “natural” winemaking that either eschews fining or accomplishes it without animal-derived fining agents in the hopes of maintaining more of a particular wine’s or vintage’s character. Even brands like Moët & Chandon and Veuve Clicquot offer vegan Champagnes.